class-wp-styles.php sends output too early on media-upload.php

[kkmuffme]

Hook a function on send_headers

<?php
add_action( 'send_headers', function foo() { header( 'X-Debug: Foo' ); } );

Open:
/wp-admin/media-upload.php?type=image&tab=library&post_id=1234

You'll get a PHP error that headers have already been sent from wp-includes/class-wp-styles.php
Given this is the "send_headers" hook, there shouldn't be any output sent at that point yet though.

[kkmuffme]

Duplicate of #63501.